We attempted to test whether the differentiated NIH/3T3 fibroblasts could be differentiated into neuronal cells without any epigenetic modification. First, a neurosphere assay was carried out, and we successfully generated neurosphere-like cells by floating cultures of NIH/3T3 fibroblasts in neural stem cell medium. These spheres have the ability to form sub-spheres after three passages, and express the neural progenitor markers Nestin, Sox2, Pax6, and Musashi-1. Second, after shifting to a differentiating medium and culturing for an additional 8 days, cells in these spheres expressed the neuronal markers β-tubulin and neurofilament 200 and the astrocytic marker glial fibrillary acidic protein (GFAP)...

The use of stem-cell therapy to treat retinal degeneration holds great promise. However, definitive methods of retinal differentiation that do not depend on recombinant proteins produced in animal or Escherichia coli cells have not been devised. Here, we report a defined culture method using low-molecular-mass compounds that induce differentiation of human embryonic stem (ES) cells and induced pluripotent stem (iPS) cells into retinal progenitors, retinal pigment epithelium cells and photoreceptors. The casein kinase I inhibitor CKI-7, the ALK4 inhibitor SB-431542 and the Rho-associated kinase inhibitor Y-27632 in serum-free and feeder-free floating aggregate culture induce retinal progenitors positive for RX, MITF, PAX6 and CHX10...